Harrow doctors were urged not to send patients to overwhelmed A&E departments last week, sparking fresh concerns over casualty closures.

Maeve O'Callaghan-Harrington, head of emergency planning at North West London Hospitals NHS Trust, wrote to Harrow GPs last week telling them the casualty units at Northwick Park Hospital and Central Middlesex Hospital were full.

Doctors were told to refer patients to short term assessment, rehabilitation and reablement services instead. There are teams based at Northwick Park as well as Central Middlesex Hospital.

Harrow West MP Gareth Thomas believes the move has cast a shadow over plans to close accident and emergency services across the capital.

He said: “This exposes the pressure the NHS is under and calls into question even more the judgement of those demanding neighbouring A&E departments are closed.

“David Cameron needs to explain how the Government can close so many A&E units without putting lives at risk."

But North West London Hospitals NHS Trust has defended its actions, saying it has not closed its A&E departments to emergency admissions. It also claims it is "normal" for these departments to be busy during the winter months.

Trust chief executive David McVittie said: “In light of the pressures we experienced over the weekend of December 8, we reminded GPs of the other services available to patients if they need to be reviewed in the community by a hospital clinician.

“I want to reassure patients that our planning for winter started some time ago and we have plans in place to help us ensure we can offer the best care during busy periods.

“As is good practice, we constantly review these plans and the resources we need. For example, there are plans to open an ambulatory care unit at Northwick Park Hospital, which will help to reduce pressure on A&E.”

Northwick Park A&E has seen a 30 per cent increase in emergency hospital admissions over the past three years and a 20 per cent increase in A&E attendances.

In a statement, NHS London added: “Under current proposals put forward by local clinicians, evidence shows that most patients could get better care if seen in urgent care centres, whilst hundreds of lives could be saved if patients with life-threatening injuries or illnesses were treated in fewer specialist centres – like London’s specialist stroke and major trauma units.

“Clinicians would not recommend changes to A&E services unless it improves patient care.  There will be no changes to NHS services unless they are led by clinicians and local people will be fully consulted.”